5. Helicobacter pylori infection Flashcards
describe H pylori the micro-organism ?
gram negative spiral urease producing , hydrogenase , catalase and oxidase several flagella microaerophilic
h pylori is associates as the causative agent for what sort of disease ?
chronic gastritis
peptic ulcers
stomach cancer
MALT lymphoma
is h pylori symptomatic ?
80 percent affected is asymptomatic
what is the route of transmission in H pylori ?
unknown can be feral oral endoscopic transmission
how does the h pylori survive inside the stomach ?
goes through the mucus layer with he help of the flagella
and away from the acidic lumen
has adhesion to stick
high dependant on urease which break down urea - and releases ammonia neutralising the gastric acid
h pylori usually colonists what part of the stomach ?
the antrum and corpus
wha are the special staining used for H pylori ?
giemsa , warthin starry stain
how to diagnose h pylori infection ?
carbon urea breath test especially looking for
13C - urea
14C - urea
can produce false negative - when using antibiotics
serology test for IgG against Hp - high sensitivity and specificity - not suitable for follow up therapy as antibodies might persist in the circulation
stool antigen testing - most specific and sensitive
biopsy with endoscopy
rapid urease test
microbiological culturing and PCR
what is the first line treatment for HP
standard triple therapy as FIRST LINE
PPI / h2 blockers two times daily 2x20mg daily
clarithromycin 2 x 500mg (macrolides)
amoxicillin 2 x 1000mg /
for 14 days
what is the second line of therapy therapy ?
alternative triple therapy levofloxacin based PPI + amoxicillin + levofloxacin or metronidazole based PPI + clarithromycin + metronidazole 2x 500mg
or
quadruple therapy - 14 days again
PPI standard +
metro/tetranidazole 4x 500g + tetracyclin 4x 500g +
bismuth 4x525g (mucosal protection)
how can you prevent h pylori ?
intramuscular vaccine for h pylori undergoing phase1 clinical trials
broccoli sprouts daily for two months reduces h pylori colonies
what is the sequential treatment of h pylori ?
PPI
amoxicillin 2 x 1g for 5-7days
then amoxicillin is substituted with clarithromycin 500mg
twice a day with tinidazole 500 mg twice a day for next 5 days
so PPI + CLARITHROMYCIN+ tinidazole/ metronidazole
what is the pathophysiology of the H pylori in chronic gastritis ?
Inflammation of the antrum → destruction of D cells → ↓ somatostatin → ↑ gastrin → ↑ production of gastric acids → duodenal ulcers
Inflammation of the gastric body → local destruction of mucosa →
↓ production of mucins and atrophy of the gastric glands → hypochlorhydria → hypergastrinemia → epithelial metaplasia → ↑ risk of gastric cancers
what are the risk factors for contracting h pylori ?
low socio economic status
race such as african americana and hispanic latinos
which disease is associated with hp infection ?
ménétrier disease - massive overgrowth of mucous foveola cells
Little or no acid production
Resulting in large gastric folds
- protein loosing gastropathy
Low blood albumin
And edema
